Who is Professor Hallux?

Professor Hallux is a scientist who is really curious about everything to do with the human body!

With the help of Nurse Nanobot he wants to find out everything he can about how the human body works.

Watch this video in which Professor Hallux and Nurse Nanobot find out more about how glasses actually work…

After that you should have a better idea about how glasses help some people see.

Why do some people need to wear glasses?

People wear glasses to help them see better.

Lots of people can see perfectly but a lot of people have trouble seeing things either far away from them or close to them – glasses can help these people see better.

Most people with glasses are either short-sighted or long-sighted.

Short-sighted

This is when people can’t see things that are far away from them, like a sign post or a theatre stage for example.

The medical word for it is Myopia.

Long-sighted

This is when people can’t see things that are close up to them, like a book for example.

The medical word for it is Hypermetropia.

Why are some people short-sighted and long-sighted?

They are both to do with what your eye does with the light as it enters the eye.

Light goes through the cornea and lens in your eye.

The lens uses muscles to change it’s shape so that it bends the light coming into your eye so that it is in focus. This makes sure that what you see is in focus and not all blurry.

When your lens is working properly it bends the light so that it comes into focus in the exact right spot in your eye – on the retina at the back of your eye.

When someone is short-sighted their eye focuses the light too soon like this.

When someone is long-sighted their eye focuses the light too late like this.

So how do the glasses help?

Glasses help the light to focus correctly on the retina.

As the light passes through the glasses lens it bends the light just enough so that it focuses exactly right on the retina.

No two eyes are the same right? How do you know what lens to put in the glasses?

When you go to the opticians they do loads of tests to check which glasses lenses you need.

During the eye test the optician will test out loads of different lenses on your eyes and use this information to find out what lenses your glasses need!

Your mission is to complete this quiz all about glasses

Click here to see the next mission all about colour blindness!

In the mean time, if you want more from professor Hallux then you can find more here.